Systems and methods for charging a cleaning solution used for cleaning integrated circuit substrates

ABSTRACT

Inventive methods, systems and compositions of cleaning integrated circuit (“IC”) substrates are described. The cleaning methods of the present invention include: charging a solution, which contains at least a solute selected to promote cleaning of the IC substrate, to produce a charged solution, such that at least a portion of the solute is present as clusters in the charged solution; and conveying the charged solution for cleaning the IC substrate. 
     The cleaning systems of the present invention include: a charging chamber for holding a solution, which contains at least a solute selected to promote cleaning of the integrated circuit substrate; and a first acoustic energy source capable of vibrating the solution in the charging chamber to produce a charged solution such that at least a portion of the solute is present as clusters in the charged solution. 
     The cleaning compositions of the present invention include: a solvent; and a solute selected to promote cleaning of the IC substrate, wherein at least a portion of the solute is present in cluster form in the solution and the solute and solvent are present in a volumetric ratio that is between about 3×10 −5 :1 and about 1×10 −24 :1.

FIELD OF THE INVENTION

The present invention relates to systems and methods for effectivelycleaning integrated circuit (“IC”) substrates. More particularly, thepresent invention relates to systems and methods for effectivelycharging a solution before it is used for cleaning IC substrates. In thecharged solution, at least a portion of the solute particles are presentin cluster form, as solute clusters. The present invention also providescompositions for effective cleaning of IC substrates.

BACKGROUND OF THE INVENTION

During the integrated circuit (“IC”) manufacturing process,contaminants, such as particles, photoresist residue and the like, areintroduced on the IC substrate surface. It is important to eliminate orreduce the presence of these contaminants as they adversely impact theperformance and function of the IC that is ultimately produced.Accordingly, various cleaning methods have been implemented to removesuch undesirable contaminants.

A cleaning method commonly used in the semiconductor industry employs aconcentrated ammonium hydroxide solution known as the Standard CleaningSolution 1 (the “SC-1 solution”). In the SC-1 solution, typically heatedammonium hydroxide, hydrogen peroxide and deionized water are present ina volume ratio of approximately 1:1:5. During cleaning, the SC-1solution contacts the substrate surface in the presence of megasonicenergy. It is believed that the SC-1 solution detaches contaminants fromthe substrate surface through surface etching and that the megasonicenergy further removes the detached contaminant from the substratesurface. Although this method has been the cleaning method of choice formost in the semiconductor industry during the last forty years, itsuffers from several drawbacks.

Concentrated cleaning solutions run the risk of unduly etching, whichappears as surface roughness, and thereby damaging the substrate surfaceand the devices undergoing cleaning. In a non-patterned semiconductorsubstrate surface, for example, over etching damages the real estate onthe substrate surface, upon which circuitry and transistor devices aresubsequently fabricated. For this reason, the resulting semiconductorchip may suffer from poor electrical performance or completemalfunction.

Dispensing highly concentrated cleaning solutions to drain posesenvironmental concerns. Consequently, the concentrated effluent streamexiting the cleaning system requires appropriate treatment. The cost ofan effluent treatment system and labor to implement the cleanup processmake the process of cleaning using the SC-1 solution expensive.

Concentrated cleaning solutions also deposit on the substrate surfaceundesirable metal contaminants which degrade device performance.Moreover, the peroxide composition of the cleaning solution typicallycontains stabilizers, which is another source of contamination thatleads to performance issues. This problem is further exacerbated whenrelatively high composition of peroxide is used as part of the cleaningsolution.

The presence of such contaminant particles even more adversely impactcurrent IC geometries. With the miniaturization of the circuitry on ICs,device sizes are currently approaching progressively smaller scales andsuch small devices densely populate the IC substrate surface.Contaminant particles of a certain size, which previously did not pose athreat to an IC's performance because the early generation ICs were notas densely populated, now have a significant impact on the electricalperformance of current ICs having miniature geometries. In fact, thesecontaminant particles can render the entire IC useless. As a result, aneffective cleaning method for removing such contaminant particles,without damaging the substrate surface, is critical to enhancing theyield of ICs.

In an attempt to circumvent the above-mentioned drawbacks, U.S. Pat. No.6,681,781 issued to Puri et al. proposes a cleaning solution formed fromultra dilute concentrations of a cleaning enhancement agent (e.g.,ammonia gas) in a solvent (e.g., water). In ultra dilute solutions, thesolvent and solute are present in volume ratios ranging from 500:1 to500,000:1. Unfortunately, this process also suffers from drawbacks.

At the high end of ultra dilute ammonium hydroxide concentrations, thereaction of ammonium hydroxide with silicon continues to produceover-etched surfaces in the current IC geometries. To minimize drawbacksof over etching, an ozonating step has been added to the cleaningprocess. As a protective measure, in this step, the substrate surfaceundergoes ozonation before it is exposed to the cleaning solutioncontaining a harsh concentration of ammonium hydroxide. Such anadditional step, however, lowers the throughput of the cleaning processand the throughput of the overall IC manufacturing process. It also addsto the expense of cleaning the substrate surface.

At the low end of ultra dilute ammonium hydroxide concentrations, thecleaning solutions are simply not effective to detach the contaminantparticle from the substrate surface. In other words, cleaning solutionshaving low concentrations of ammonium hydroxide do not sufficientlyreact with the substrate surface to detach a desirable amount ofcontaminant particles from it. Conventional wisdom, as a result, deemscleaning solutions having low concentrations of a cleaning enhancingagent, such as ammonium hydroxide, to be ineffective and undesirable.

What is therefore needed are improved systems and methods of cleaningICs, which do not suffer the drawbacks of the current IC cleaningprocesses and effectively clean IC substrate surfaces having the currentminiature geometries.

SUMMARY OF THE INVENTION

To achieve the foregoing, the present invention provides systems andmethods for effectively charging a solution before using it for cleaningthe integrated circuit (“IC”) substrate. Charging a solution impacts thedistribution of the solute particles throughout the solution.Specifically, in a charged solution, the solute particles are arrangedin cluster form and exist as solute clusters. By way of example, eachcluster can contain an average of between about 100 and about 200 solutemolecules. In sharp contrast, in conventional cleaning solutions, thesolute particles are distributed randomly, and not in cluster form.

While wishing not to be bound by theory, the solute clusters in acharged solution of the present invention provide an effective removalmechanism for the detached contaminant particle from the substratesurface. It is believed that the solute clusters trap the contaminantparticles, which are initially detached from the substrate surface fromthe application of acoustic energy. In the absence of such soluteclusters, as is the case with conventional cleaning solutions, it isbelieved that there exists no mechanism to trap such detached particles,which subsequently land on and adhere to the substrate surface.

The present invention recognizes, in accordance with one embodiment,that applying acoustic energy to relatively dilute solutions promotescharging. For example, charging can be accomplished by applying acousticenergy to dilute solutions, where the solute is present in the solventat a volume ratio that is between about 3×10⁻⁵:1 and about 1×10⁻²⁴:1.Such dilute solutions may cover solute concentrations in the ultradilute regime and at “near zero dilutions.” When a solute is present ina solvent at a volumetric ratio that is between about 3×10⁻⁵:1 and5×10⁻⁵:1, the dilution of the resulting solution is considered to be inthe ultra dilute regime. Furthermore, the term “near zero dilution,” asused in this specification, refers to dilutions where the solute ispresent in the solvent at a volumetric ratio that is between about5×10⁻⁵:1 and 1×10⁻²⁴:1.

Regardless of whether the dilution of the solute is in the ultra diluteregime or at near zero dilution, the teachings of the present inventionallow for effective cleaning of the substrate, without suffering fromthe drawbacks encountered when using concentrated or dilute conventionalcleaning solutions. In fact, given that relatively dilute solutions aredesirable for charging, i.e., forming solute clusters, solutions having“near zero dilutions” are preferred in the present invention. Use of“near zero dilutions” for cleaning substrates goes against conventionalwisdom because conventional cleaning techniques require higherconcentrations of the solute to facilitate particle removal through areaction mechanism. As explained above, the particle removal mechanismof the present invention is primarily focused on promoting solutecluster formation, and not focused on promoting the reaction between thesolute and the substrate surface.

The present invention provides effective methods for cleaning an ICsubstrate. Inventive methods include: (i) charging a solution, whichcontains at least a solute selected to promote cleaning of theintegrated circuit substrate, to produce a charged solution, wherein atleast a portion of the solute is present as clusters in the chargedsolution; and (ii) conveying the charged solution for cleaning theintegrated circuit substrate.

In accordance with one embodiment of the present invention, charging ofthe solution is carried out by vibrating the solution, preferably byusing megasonic energy. Preferably, the solute is ammonium hydroxide. Inaccordance with yet another embodiment of the present invention, thecharging step includes diluting the solution such that the solute ispresent in a solvent in a volumetric ratio that is between about5×10⁻⁵:1 and about 1×10⁻²⁴:1, preferably between about 1×10⁻⁶:1 andabout 1×10⁻²⁴:1, and more preferably between 1×10⁻⁸:1 and about1×10⁻²⁴:1.

In one embodiment, cleaning methods of the present invention furtherinclude: (i) diluting the charged solution to produce a cleaningsolution; and (ii) using the cleaning solution for cleaning theintegrated circuit substrate. According to this embodiment, the chargedsolution can be further charged to a greater extent by increasing itsdilution. In the cleaning solution, the solute may be present in asolvent in a volumetric ratio that is between about 5×10⁻⁵:1 and about1×10⁻²⁴:1, which range ensures that the cleaning solution is effectivelycharged. Another step of this embodiment includes applying acousticenergy to said cleaning solution, preferably by a megasonic device.Before charging the solution, the present invention also contemplatesmixing a solvent and the solute to produce the solution. Preferably, thesolvent is deionized water. In certain embodiments, mixing produces thesolution having the solute present in the solvent in a volumetric ratiothat is between about 3×10⁻⁵:1 and about 1×10⁻²⁴:1. Cleaning of thesubstrate surface can be carried out at about 30° C. or below 30° C.

In another aspect, the present invention provides a system for cleaningintegrated circuit substrates. The system includes: (i) a chargingchamber for holding a solution, which contains at least a soluteselected to promote cleaning of the integrated circuit substrate; and(ii) a first acoustic energy source capable of vibrating the solution inthe charging chamber to produce a charged solution, wherein at least aportion of the solute is present as clusters in the charged solution.

The system may further include a processing chamber for cleaning theintegrated circuit substrate using the charged solution. In accordancewith one embodiment of the present invention, the system includes asecond acoustic energy source for vibrating contents of the processingchamber during cleaning the integrated circuit substrate. In preferredembodiments, the present invention further includes a mixing chamber formixing a solvent and the solute to produce the solution before thecharging step commences. A first connection between a solvent reservoirand at a location on the second connection may also be provided fordiluting the charged solution before it enters the processing chamber.The second connection defines the connection between the chargingchamber and the processing chamber so that the charged solution can beconveyed from the charging chamber to the processing chamber.

In yet another aspect, the present invention provides a composition of asolution used for cleaning integrated circuit substrates. Thecomposition includes a solvent and a solute, which is selected topromote cleaning of the integrated circuit substrate. At least a portionof the solute is present in cluster form in the solution and the soluteand solvent are present in a volumetric ratio that is between about3×10⁻⁵:1 and about 1×10⁻²⁴:1. In a preferred embodiment, the solute andsolvent are present in a volumetric ratio that is between about 1×10⁻⁶:1and about 1×10⁻²⁴:1.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram of a cleaning system, according to one embodiment ofthe present invention, for effectively cleaning integrated circuitsubstrates.

FIG. 2A shows the random distribution of the solute particles in anuncharged solution.

FIG. 2B shows the solute particles arranged in cluster form in a chargedsolution, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF INVENTION

The present invention provides systems, methods and compositions foreffectively cleaning integrated circuit (IC) substrates. Conventionalwisdom dictates that for effectively cleaning IC substrates, high enoughconcentrations of the solute, which is typically an active cleaningingredient in the cleaning solution, should be used. According to suchwisdom, it is believed that high concentrations of the solute react withthe substrate surface to detach contaminant particles therefrom.Predicated on this belief, conventional wisdom teaches away from usingcleaning solutions with relatively low solute concentrations.

In the present invention, however, relatively low solute concentrationsof the solute are preferred because they promote charging of a solution.It is believed that in a charged solution, solute particles, which arearranged as clusters, trap detached contaminant particle for effectiveremoval from the substrate. As a result, the present invention focuseson forming solute clusters for effective cleaning of IC substrates.Notably, the inventive cleaning systems and methods described herein notonly provide a way to clean substrates using relatively low soluteconcentrations, which are deemed ineffective in conventional cleaning,rather such low solute concentrations represent preferred embodiments ofthe present invention.

FIG. 1 shows a cleaning system 100, according to one embodiment of thepresent invention, for effectively cleaning IC substrates. System 100has three chambers—a mixing chamber 110 for mixing a solute and asolvent to form a solution, a charging chamber 118 for charging thesolution and a processing chamber 126 for cleaning the IC substratesusing the charged solution. Each of mixing chamber 110 and chargingchamber 118 connect through separate connections to processing chamber126. Specifically, a first connection 132 connects mixing chamber 110 toprocessing chamber 126 and a second connection 130 connects chargingchamber 118 to processing chamber 126. As will be explained below, firstconnection 132 can also be used to convey a solvent from its reservoirdirectly to processing chamber 126.

Mixing chamber 110 receives a solvent stream from a solvent reservoir102 and the solute stream from a solute reservoir 104 through valves 106and 108, respectively. A valve 112 is activated to convey the contentsof mixing chamber 110 to charging chamber 118. Charging chamber 118comes equipped with a first acoustic energy source 114 and a couplingchamber 116 for coupling the continuous energy transmission into thecharging chamber. Contents of mixing chamber 110 can also be emptiedinto processing chamber 126 through first connection 132 when valves 112and 120 are activated. As shown in FIG. 1, solvent from solventreservoir 102 can be conveyed through mixing chamber 110 and firstconnection 132 to processing chamber 126. Using a similar path, solventfrom solvent reservoir 102 can also be conveyed through valve 106,mixing chamber 110 and first connection 132 to a location on the secondconnection where the charged solution is diluted, before it isintroduced into processing chamber 126. Contents of charging chamber 118are conveyed to processing chamber through second connection 130 whenvalve 120 is activated.

Similar to charging chamber 118, processing chamber 126 is also fittedwith a second acoustic energy source 122 and a coupling chamber 124 forcoupling the continuous energy transmission into processing chamber 126.Inside processing chamber 126, a sparger 134 facilitates welldistributed flow of the charged solution for effectively cleaning avertically disposed IC substrate 128, which is secured on a suitablecarrier (not shown to facilitate illustration).

Mixing chamber 110 may be any equipment known in the art that cancontrollably combine a flow of at least one liquid with a flow of atleast one gas. Charging chamber 118 and processing chamber 126 can bemade of any material known to be a good transmitter of acoustic energy.These chambers are preferably made from quartz. Although FIG. 1describes three chambers as three separate vessels, it is possible thatthe three chambers could be incorporated into two vessels or a singlevessel. The preferred embodiment, however, is to have three separatevessels as shown in FIG. 1.

Acoustic energy sources 114 and 122 can be any source that suppliesmegasonic energy and the like. Charging chamber 118 and processingchamber 126 are ideally placed above their corresponding acoustic energysources and their coupling chambers. Use of megasonic energy is,however, preferred because it is more effective at removing smallerparticles from the substrate surface. Although the megasonic device usedin system 100 can have outputs as high as 5 Watts/cm² and higher, it ispreferable to use an output of 3 Watts/cm² and lower. Suitable equipmentfor generating megasonic energy is commercially available from a varietyof vendors. Such equipment should, however, preferably include agenerator and a series special transducers or the like. By way example,megasonic devices, which are commercially available from KaijoCorporation of Japan and PCT Systems, Inc. of Fremont, Calif. work well.

Although in FIG. 1, one IC substrate 128 is shown inside processingchamber 126, those skilled in the art will recognize that in certainembodiments, processing chamber 126 can be designed to hold more thanone substrate or a cassette of many substrates. In preferredembodiments, however, processing chamber 126 is designed to clean one ICsubstrate at a time in series. FIG. 1 also shows that substrate 128 isoriented vertically during cleaning operations inside processing chamber126. It is, however, not necessary for the substrate to be vertical. Asubstrates oriented such that its surface is titled at an angle in therange from about zero degrees to about ten degrees can be effectivelycleaned using the inventive systems and methods described herein. Whenmore than one planar substrate (e.g., a semiconductor wafer) issimultaneously cleaned inside processing chamber 126, a slight tilt awayfrom the vertical, i.e., ninety degrees, is desired to prevent adjacentsubstrates from being jostled against each other. In those embodiments,where a substrate carrier is used, a slight tilt prevents the substratesfrom being jostled against the carrier. Such titling is optional andunder certain circumstances may not be desirable. In a substratecarrier, substrates are arranged face to face, back to back, face toback or back to face. Face to face and back to back are, however,preferred orientations.

A typical cleaning process in system 100 begins when a solvent,typically deionized water, stored in solvent reservoir 102 flows tomixing chamber 110 by activating valve 106. Similarly, a solute fromsolute reservoir 104 enters the same chamber 110 via valve 108 so mixingmay commence to form a solution. Solute reservoir 104 may contain anysolute that facilitates removal of a particulate contaminant from thesubstrate surface. In certain embodiments of the present invention,solute reservoir 104 contains ammonium hydroxide as either aconcentrated solution in liquid form or as an aqueous solution. In apreferred embodiment, solute reservoir 104 contains ammonia gas, whichallows the use of ammonium hydroxide in extremely low concentrations. Insuch preferred embodiments, before mixing ammonia gas with deionizedwater, ammonia gas is filtered to bring its purity to about 99.99999%.Those skilled in the art will recognize that depending on the type ofparticulate contaminants to be removed from the substrate surface, othertypes of solutes, different from ammonium hydroxide, may be used. By wayof example, a solution includes other chemicals, such as O₃, HC₁, H₂O₂,NH₄OH and HF. These solutes are usually mixed with deionized water to asolution which is subsequently used for cleaning. Alkaline basedsolutions tend to remove particles of silicon, carbon, and theirderivatives. Acid based solutions, such as that made using HCl, removemetal contaminants from the substrate surface. In those embodimentswhere ammonium hydroxide is used, the volumetric ratio of ammoniumhydroxide to deionized water is generally between about 3×10⁻⁵:1 andabout 1×10⁻⁹:1, and preferably between about 1×10⁻⁶:1 and about1×10⁻⁸:1.

By activating valve 112, the solution formed in mixing chamber 110 isconveyed to charging chamber 118. An acoustic energy source 114,preferably a megasonic device, through a coupling chamber 116 suppliessufficient energy to charge the solution to create a coherent solutioninside charging chamber 118. As a result, inside chamber 118, arelatively dilute solution is transformed from an uncharged state to acharged state by the aid of a megasonic device.

FIGS. 2A and 2B illustrate the difference in solute particledistribution from a solution's uncharged state to a charged state. InFIG. 2A, which shows an uncharged solution 200, solute particles 202 arerandomly distributed throughout solution 200. In FIG. 2B, which shows acharged solution 210, solute particles 214 are organized in solution 210as clusters 212. In a preferred embodiment of the present invention, anaverage number of molecules of solute 214 in clusters 212 is betweenabout 100 and about 200 molecules per cluster. Those skilled in the artwill recognize that in each of solutions 200 and 210, the soluteparticles are dissolved in a solvent, which is not shown in FIGS. 2A and2B to simplify illustration and facilitate discussion. Furthermore,clusters 212 need not have a circular shape with a smooth exterior, asshown in FIG. 2B. Rather, clusters 212 are generally of any irregularshape.

Although cluster formation is predominant at 0° C., cleaning insideprocessing chamber 126 should be carried out at about 30° C. or below30° C. Test data obtained from various experiments suggests that at roomtemperature or at about 30° C., there are sufficient number of solutemolecules within the clusters to trap the detached contaminant particlesfrom the substrate surface and provide the necessary electromotive force(“EMF”) for holding onto such particles. At higher temperatures, clusterformation appear to melt away and only a few molecules are left within avery small cluster. Consequently, substrate cleaning is more effectiveat around room temperature than at relatively higher temperatures.

The charged solution exiting charging chamber 118 has solute present inthe solvent in a volumetric ratio that is between about 5×10⁻⁵:1 andabout 1×10⁻²⁴:1, preferably between about 1×10⁻⁶:1 and about 1×10²⁴:1,and more preferably between about 1×10⁻⁸:1 and about 1×10⁻²⁴:1.

By activating valve 120, some of the charged solution is introducedthrough first connection 130 into processing chamber 126 for cleaningsubstrate 128. Although only one inlet to process chamber 126 is shownin FIG. 1, those skilled in the art will recognize that if more than onestream of solution is required for cleaning then additional inlets tochamber 126 can be provided.

Inside processing chamber 126, the charging solution is introduced by asparger 134 located at the bottom. The charging solution fills theprocessing chamber 126 from the bottom as described in U.S. Pat. No.6,681,781 issued to Puri et al. Processing chamber 126 may also comeequipped with a drain valve and drain line (not shown to simplifyillustration) to dispense the effluent stream. Cleaning of the substrateoccurs by causing the charged solution to contact the surface. This isaccomplished by any one of spraying the solution onto the surface, bysubmerging the surface in a charged solution or flowing the solutionpast the substrate surface. Acoustic energy is applied to the substratesurface, while it is contacting the charged solution.

In preferred embodiments as shown in FIG. 1, system 100 is designed tocharge to a greater extent a charged solution stream flowing out ofcharging chamber 118. First connection 132 facilitates diluting thischarged solution using more solvent from solvent reservoir 102 andconveying it to the charged solution inside second connection 130,before it is introduced inside processing chamber 126. Specifically, byactivating valves 106 and 112 such solvent is provided from solventreservoir 102 to the charged solution within second connection 132. Insuch dilute charged solution, solute is present in a solvent in avolumetric ratio that is between about 5×10⁻⁵:1 and about 1×10⁻²⁴:1.This preferred embodiment, provides the flexibility of using smallamounts of charged solution residing in charging chamber 118 and furtherdiluting it to produce a more effectively charged solution.

Although not shown in FIG. 1, charging chamber 118 can be fitted with arecirculation scheme having one more chambers arranged to recirculatethe charged solution. In each such chamber, progressive dilutions of thecharged solution are possible. The above-described scheme allowseffective dilutions of charged solutions having relatively lowconcentrations of the solute. The flow schemes described above formixing, charging and cleaning can be carried out in continuous mode,batch and semi-batch mode.

In summary, the present invention relies upon very high pH of thecharged near-zero solute dilutions in the cleaning solution to captureand transfer the particulate contaminants which are further detachedfrom the substrate surface using megasonic energy.

The present invention represents a marked improvement over theconventional systems, methods and compositions for cleaning ICsubstrates. As explained above, the present invention prefers use ofcharged solutions, which have relatively low concentrations of thesolute, i.e., dilutions in the ultra-dilute regime or having “near zerodilutions.” Consequently, the cleaning systems and methods of thepresent invention are environmentally green. In other words, they do notrequire the additional expense of equipment and labor to treat theeffluent stream before draining, which is required by the conventionalcleaning systems and methods. Furthermore, in the cleaning system andmethods according to the present invention, the significant costassociated with disposing chemicals is eliminated.

According to conventional cleaning methods, the solute concentration isheated to facilitate substrate etching for particle removal. Thisrequires substantial time and equipment. The solute in the presentinvention, however, effectively cleans at room temperature conditionsand does not require such heating. The present invention, therefore,obviates the need for heating equipment and additional processing time.

As explained above, conventional cleaning systems and methods rely uponconcentrated solution to etch the substrate surface and thereby removeparticulate contaminants. The conventional cleaning, therefore,introduces undesired surface roughness that degrades the electricalperformance of the ultimately produced IC. In the present invention,however, the IC substrates are cleaned using charged solutions havinglow concentrations of the solute. In other words, given that very smallquantities of chemicals are being used for cleaning, the substratesurface is unetched. Another advantage of using small quantities ofchemicals is that no residue of stabilizers and metal contaminantsremain on the substrate surface. In other words, substrates cleanedaccording to the present invention have little or no stabilizer residueand metal contaminants thereon because chemicals in very smallquantities are used during the cleaning process. A yet another advantageof using small quantities of chemicals is that there is no need for apretreatment step before cleaning the substrate. The present invention,which can effectively clean substrates at “near zero dilutions,” do notrequire an additional pretreatment step, such as ozonation, which isrequired by conventional cleaning techniques. This also translates intoincreased throughput when cleaning according to the present invention.

Substrate cleaning, according to the present invention, occurs veryrapidly. By way of example, about three to five minutes, and typicallyabout three minutes is sufficient time to effectively clean a substrate.Consequently, the present invention provides a relatively higherthroughput. Moreover, if a substrate surface is not sufficiently cleanafter a single cleaning cycle, then more than one cleaning cycle can beimplemented to more effectively clean that surface, without degradingit. Multiple cleaning cycles in the present invention, actually improvethe quality of the surface and do not introduce undesired surfaceroughness, stabilizers or metal contaminants, which are introduced whencleaning according to conventional methods is performed. Those skilledin the art will recognize that such multiple cleaning cycles inconventional cleaning typically destroys the substrate surface.

Although certain examples have been described in terms of cleaningsemiconductor substrates, those skilled in the art will recognize thatthe inventive systems, methods and compositions described herein can beused for other IC substrates. For example, the inventive systems,methods and compositions can be used for effective cleaning of masks,disks, flat panels, liquid crystal displays, thin film heads, photomasks, and lenses.

1-17. (canceled)
 18. A system for cleaning integrated circuitsubstrates, comprising: a charging chamber for holding a solution, whichcontains at least a solute selected to promote cleaning of saidintegrated circuit substrate; and a first acoustic energy source capableof vibrating said solution in said charging chamber to produce a chargedsolution, wherein at least a portion of said solute is present asclusters in said charged solution.
 19. The system of claim 18, furthercomprising a processing chamber for cleaning said integrated circuitsubstrate using said charged solution.
 20. The system of claim 19,further comprising a second acoustic energy source for vibratingcontents of said processing chamber during cleaning said integratedcircuit substrate.
 21. The system of claim 18, further comprising amixing chamber for mixing a solvent and said solute to produce saidsolution.
 22. The system of claim 18, further comprising a secondconnection between said charging chamber and said processing chamber forconveying said charged solution from said charging chamber to saidprocessing chamber.
 23. The system of claim 22, further comprising afirst connection between a solvent reservoir and said second connectionfor diluting said charged solution before it enters said processingchamber. 24-27. (canceled)